Adhesive layer composition for in-mold decoration

ABSTRACT

This invention relates to compositions suitable for the formation of an adhesive layer used for in-mold decoration.

This application claims the priorities under 35 USC 119(e) of U.S.Provisional Application No. 60/589,708 filed on Jul. 20, 2004. The wholecontent of the priority application is incorporated herein by referencein its entirety.

FIELD OF THE INVENTION

This invention relates to compositions suitable for the formation of anadhesive layer used for in-mold decoration.

BACKGROUND OF THE INVENTION

In-mold decoration processes involve decorating objects as they areformed, in mold, of a heated plastic material being injected into a moldcavity. Usually a tape or strip of a decorating or protective materialis automatically or manually advanced, pre-fed and positioned in themold cavity at each molding cycle, interfacing therein with the plasticmaterial as it is filled into the mold cavity, under heat and pressure.As the object is formed, the decorating material forms on the surface ofthe object and becomes an integral and permanent part of the object,through thermal transfer in the in-mold decoration process. Othermolding processes such as thermal forming, blow molding and compressionmolding or stamping may also be used for the transfer of the decoratingor protective material. Sometimes the process may also be called in-moldlabeling or in-mold coating, and the transferable protective materialmay be called a thermal transfer overcoat or durable coat layer.

The decoration tape or strip usually comprises a carrier layer, arelease layer, a durable layer, an adhesive or tie-coat layer and also alayer of decorative designs (metal or ink). After the injection moldingtransfer, the carrier layer and the release layer are removed, leavingthe durable layer as the outmost layer. The durable layer serves as aprotective layer with scratch resistance, mar or abrasion resistance andsolvent resistance to protect the decorative designs and also the moldedobject. The adhesive layer is incorporated into the decoration tape orstrip to provide optimum adhesion of the decoration tape or strip to thetop surface of the molded object.

However, the currently available decoration tape or strip has manydisadvantages. For example, when the carrier and release layers areremoved, the durable layer cannot be cleanly separated from the releaselayer, especially at the edges of the molded object. The residualdurable layer at the edges has to be removed manually. As a result,fragments of the residual durable layer inevitably generate debris whichnot only causes contamination to the production environment but alsoreduces the production yield. This problem is even more pronounced whenthe molded object has a small hollow structure, such as a speaker andear pieces of a cell phone cover.

The problem is most likely caused by poor fracture characteristics ofthe decoration tape or strip and/or the inappropriate balance betweenthe cohesion strength of the durable and adhesive layers and theadhesion strength at the interface between, such as the durable andrelease layers, the durable and ink layers, the durable and metallayers, the adhesive and metal layers, the durable and adhesive layersand/or the adhesive layer and the molding plastic material.

SUMMARY OF THE INVENTION

The first aspect of the present invention is directed to an improvedadhesive layer of a decoration tape or strip or a thermal transferprinting or coating layer. The improved adhesive layer is coated on adecorative layer or a functional coating and/or printing layer tofacilitate the transfer of the decoration or functional coating and/orprinting onto an object of interest by heat, pressure or a combinationthereof. The transfer may be accomplished by a method such as injectionmolding, hot stamping, heat laminator or thermal head printing.

The adhesive layer comprises an adhesive binder and a polymericparticulate material. The polymeric particulate material has a Tg (glasstransition temperature) higher than about 45° C., preferably higher thanabout 55° C. and more preferably higher than about 65° C. Theconcentration of the polymeric particulate material is preferably in therange of about 5 to about 50% by weight, more preferably in the range ofabout 10 to about 40% by weight. The polymeric particulate material isdispersed in the adhesive binder and preferably remains in a dispersedstate during the thermal transfer process.

The polymeric particulate material is preferably of small particleshaving an average size of < about 1 um, more preferably < about 0.2 umand most preferably < about 0.15 um and is immiscible with the adhesivebinder.

In the context of the present invention, two materials are “miscible” ifthey form a single phase or a material of a single Tg, after the two arethoroughly blended by heat, solvent or mechanical means.

The second aspect of the present invention is directed to an adhesivelayer of the present invention wherein said polymeric particulatematerial is refractive index matched to the adhesive binder. Thedifference between the refractive indexes of the two materials ispreferably less than about 0.1, more preferably less than about 0.05.

The third aspect of the present invention is directed to an adhesivelayer of the present invention wherein said polymeric particulatematerial is core-shell particles having a high Tg shell that is at leastpartially miscible with the adhesive binder. The Tg of the shell ishigher than about 45° C., preferably higher than about 55° C. and morepreferably higher than about 65° C. Preferably the core is refractiveindex matched to the shell or the blend of the shell and the adhesivebinder.

The fourth aspect of the present invention is directed to an adhesivelayer of the present invention further comprising about 1 to about 20%by weight, preferably about 3 to about 15% by weight, of an inorganicparticulate material having an average particle size of less than about0.2 um, preferably less than about 0.1 um and more preferably less thanabout 0.05 um.

The fifth aspect of the present invention is directed to an adhesivelayer of the present invention further comprising about 0.2 to about 5%by weight, preferably about 1 to about 3% by weight, of an organic orinorganic particulate material having an average particle size in therange of about 0.5 to about 6 um, preferably in the range of about 1 toabout 3 um.

The sixth aspect of the present invention is direct to an adhesive layerof the present invention comprising an adhesive binder, an organic or afirst inorganic particulate material having an average particle size inthe range of about 0.5 to about 6 um, preferably in the range of about 1to about 3 um, and a second inorganic particulate material having anaverage particle size smaller than about 0.2 um, preferably smaller thanabout 0.1 um and more preferably smaller than about 0.05 um. The totalconcentration of the inorganic particulate material(s) is preferablyabout 5 to about 50% by weight, preferably about 10 to about 35% byweight.

In one embodiment of this aspect of the invention, the adhesive layermay comprise an adhesive binder, a polymeric particulate material, afirst inorganic particulate material having an average particle size oflarger than about 0.5 to about 6 um, preferably larger than about 1 toabout 3 um, and a second inorganic particulate material having anaverage particle size smaller than about 0.2 um, preferably smaller thanabout 0.1 urn and more preferably smaller than about 0.05 um. Theconcentration of the polymeric particulate material is preferably in therange of about 5 to about 50% by weight, more preferably in the range ofabout 10 to about 40% by weight. The polymeric particulate material ispreferably small particles having an average size of < about 1 um,preferably < about 0.2 um and more preferably < about 0.15 um.

The seventh aspect of the present invention is direct to an adhesivelayer of the present invention further comprising a solid plasticizerhaving a melting point between about 65 to about 130° C., preferablybetween about 80 to about 115° C. For example, the adhesive layer maycomprise an adhesive binder, a polymeric particulate material and asolid plasticizer.

The adhesive layer of the present invention provides desirable fractureproperties and as a result, cracking at the edges of the object duringthe transfer process such as injection molding, may be initiated andpropagated efficiently during the injection molding process and thesubsequent mold-part separation process. This feature enables a cleanseparation of the decoration or functional layer from the carriersubstrate at the edges of the object, particularly at the edges of ahollow structure.

In addition, the adhesive layer of the present invention also provideshigh degree of transmission, high blocking resistance, high hardness andsufficient adhesion, even for complicated three-dimensional objects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section view of an in-mold decoration tape or strip.

FIG. 2 shows how the in-mold decoration tape or strip is fed into a moldcavity.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a cross-section view of an in-mold decoration tape or strip(10) which comprises a carrier layer (15), a release layer (11), adurable layer (12), a decorative design layer (13), and an adhesivelayer (14).

In an in-mold decoration process, the tape or strip (10) is fed into amold cavity (16) automatically or manually with the carrier layer (15)in contact with the mold surface as shown in FIG. 2. The tape or stripmay be thermally formed to a desirable shape before the feeding step.

The carrier (15), release (11) and durable (12) layers may be formed bymethods known in the art and all of the previously known carrier,release and durable layers may be incorporated into the presentinvention.

For example, the carrier layer (15) usually is a thin plastic film witha thickness from about 3.5 to about 100 microns, preferably about 10 toabout 50 microns. Polyethylene terephthalate (PET), polyethylenenaphthate (PEN) or polycarbonate (PC) film is particularly preferredbecause of their low cost, high transparency and thermomechanicalstability.

The release layer (11) allows the in-mold decoration tape or strip to bereleased from the carrier layer in a manner that minimizes damage to thedurable layer (12) and the decorative layer (13) and also enables afully automated roll transfer process during molding. The release layerusually is a low surface tension coating prepared from a material suchas wax, paraffin or silicone or a highly smooth and impermeable coatingprepared from a material selected from the group consisting of melamineformaldehyde, metal thin film such as Al or Sn, crosslinkedpolyacrylates, silicone acrylates, epoxides, vinyl esters, vinyl ethers,allyls and vinyls, unsaturated polyesters or blends thereof. The releaselayer may comprise a condensation polymer, copolymer, blend or compositeselected from the group consisting of epoxy, polyurethane, polyimide,polyamide, melamine formaldehyde, urea formaldehyde, phenol formaldehydeand the like.

The release layer as disclosed in U.S. Ser. No. 60/564,018 filed on Apr.20, 2004, the content of which is incorporated herein by reference inits entirety, is also suitable. Such a release layer compositioncomprises an amine-aldehyde condensate and a radical inhibitor orquencher.

The durable layer (12) serves as a protective layer for the decorativelayer. Suitable raw materials for the durable coating may include, butare not limited to, radiation curable multifunctional acrylatesincluding epoxy acrylates, polyurethane acrylates, polyester acrylates,silicone acrylates, glycidyl acrylates, epoxides, vinyl esters, diallylphthalate, vinyl ethers and blends thereof. The durable layer maycomprise a condensation polymer or copolymer, such as epoxy,polyurethane, polyamide, polyimide, melamine formaldehyde, ureaformaldehyde or phenol formaldehyde. The durable layer may also comprisea sol-gel silicate or titanium ester.

The durable layer may be partially or fully cured. If partially cured, apost curing step will be employed after the molding and/or transferringstep to enhance the durability, particularly hardness, scratch and oilresistance.

To improve the release properties, the raw material, particularly thelow molecular weight components of the durable layer, is preferably notpermeable into the release layer. After the durable layer is coated andcured or partially cured, it should be marginally compatible orincompatible with the release layer. Binders and additives, such asthickeners, surfactants, dispersants, UV stabilizers or antioxidants,may be used to control the rheology, wettability, coating properties,weatherability and aging properties. Fillers such as silica, Al₂O₃,TiO₂, CaCO₃, microcrystalline wax or polyethylene, Teflon or otherlubricating particles may also be added to improve, for example, scratchresistance and hardness of the durable layer.

The durable layers as disclosed in U.S. Ser. No. 60/532,003 filed onDec. 22, 2003, U.S. Ser. No. 60/563,997 filed on Apr. 20, 2004 and U.S.Ser. No. 60/541,797 filed on Feb. 3, 2004, the contents of all of whichare incorporated herein by reference in their entirety, are alsosuitable.

The durable layer is usually about 2 to about 20 microns, preferablyabout 3 to about 8 microns in thickness.

The decorative layer (13) may be a metallic layer or an ink layer formedfrom a method such as vapor deposition or sputtering, optionallyfollowed by a patterning process. The ink pattern may be formed by aprinting process such as gravure, flexo, screen, sublimation heattransfer or the like on a substrate layer. The substrate layer may be aplastic layer or an insulator-coated metal or metal oxide foil formedfrom carbon steel, stainless steel, Al, Sn, Ni, Cu, Zn, Mg or an alloyor oxide thereof.

The decorative designs may also be pre-shaped by thermoforming. In thiscase, the carrier layer (15) becomes part of the molded object. Thedecorative layer having raised or recessed patterns is typically in therange of about 0.2 to about 1 mm, preferably in the range of about 0.3to about 0.7 mm, in thickness. It is usually thermoformed from an ABS(acrylonitril-butadiene-styrene), polycarbonate, acrylics, polystyreneor PVC sheet in a mold.

Alternatively, the decorative layer may be also pre-shaped by highpressure forming involving the use of high-pressure air to createdecorative designs on a film. The decorative layer may also be formed byhydroforming in which a hydrostatic bladder, rather than air, serves asthe forming mechanism.

The adhesive layer (14) disclosed herein constitutes the presentinvention. The adhesive layer comprises an adhesive binder and apolymeric particulate material.

In the context of the present invention, suitable adhesive binders mayinclude, but are not limited to, polyurethane, acrylics, SBR(styrene-butadiene rubber), polybutadiene, polyamides, pyrrolidonecopolymers, oxazolidone copolymers, vinylidene chloride copolymers,vinylacetate copolymers such as EVA (ethylene-vinylacetate or vinylalcohol copolymers), polyesters and derivatives or blends thereof, withpolyurethane, acrylics or hybrids thereof as preferred. Latex adhesivebinders or hydrocarbon dispersion adhesives are more preferred sincethey generally provide a wider process window for coating onto thedurable layer of a decoration tape or strip or thermal transfer coating.

In one embodiment, the adhesive binder is formed from a film formingpolyurethane latex. To facilitate the film formation of the adhesivebinder, a fugitive coalescing solvent, such as toluene, xylene, ethylacetate, butyl acetate, methyl ethyl ketone, acetone or N-methylpyrrolidone, may be added.

The melt flow temperature or the thermal activation temperature of theadhesive binder which is the continuous phase of the adhesive layer ispreferably lower than the injection molding temperature or the transferprinting temperature. Preferably the thermal activation temperature islower than about 200° C., preferably lower than about 170° C. and morepreferably lower than about 140° C.

The adhesive binder may take up about 40% to about 90%, preferably about50% to about 85% and more preferably about 60% to about 75% by weight,of the adhesive layer.

The polymeric particulate material preferably has a Tg (glass transitiontemperature) higher than about 45° C., preferably higher than about 55°C. and more preferably higher than about 65° C. The polymericparticulate material is dispersed in the adhesive binder and preferablyremains in a dispersed state during the thermal transfer process.

The average particle size of the polymeric particulate material ispreferably less than about 1 um, more preferably less than about 0.2 umand most preferably less than about 0.15 um.

In the context of the present invention, the polymeric particulatematerial may be a dispersion or latex prepared by emulsionpolymerization, dispersion polymerization, direct or inverseemulsification, followed by chain extension or interfacialpolymerization from a monomer such as acrylates, methacrylates, styrenesor other vinyl monomers, multifunctional isocyanates and polyols,multifunctional acid chlorides or anhydrides and polyamines or polyols,and the like.

The concentration of the polymeric particulate material is preferably inthe range of about 5 to about 50% by weight, more preferably in therange of about 10 to about 40% by weight.

In another aspect of the present invention, the adhesive layer comprisesa polymeric particulate material that is refractive index matched to theadhesive binder. The difference between the refractive indexes of thetwo materials is preferably less than about 0.1, more preferably lessthan about 0.05.

A further aspect of the invention is directed to an adhesive layerwherein said

polymeric particulate material is core-shell particles. Each of thecore-shell particles has a shell which is at least partially misciblewith the adhesive binder. In one embodiment, the Tg of the shell ishigher than about 45° C., preferably higher than about 55° C. and morepreferably higher than about 65° C. Preferably the core is refractiveindex matched to the shell or the blend of the shell and the adhesivebinder.

The core-shell particles may be prepared by, for example, emulsionpolymerization with step-wise addition of monomers.

In addition to the adhesive binder and the polymeric particulatematerial, the adhesive layer may further comprise an inorganicparticulate material. In the context of the present invention, theinorganic particulate material may be CaCO₃, BaSO₄, silica, glass beads,bentonite, clay or the like.

In another aspect of the present invention, the adhesive layer mayfurther comprise about 1 to about 20% by weight, preferably about 3 toabout 15% by weight, of an inorganic particulate material. The inorganicparticulate material may have an average particle size of less thanabout 0.2 um, preferably less than about 0.1 um and more preferably lessthan about 0.05 um.

Another aspect of the present invention is directed to an adhesive layerof the present invention further comprising about 0.2 to about 5% byweight, preferably about 1 to about 3% by weight, of an organic orinorganic particulate material. The -organic or inorganic particulatematerial may have an average particle size in the range of about 0.5 toabout 6 um, preferably in the range of about 1 to about 3 um.

A further aspect of the present invention is direct to an adhesive layerof the present invention comprising an adhesive binder, an organic or afirst inorganic particulate material having an average particle size inthe range of about 0.5 to about 6 um, preferably in the range of about 1to about 3 um, and a second inorganic particulate material having anaverage particle size smaller than about 0.2 um, preferably smaller thanabout 0.1 um and more preferably smaller than about 0.05 um. The totalconcentration of the inorganic particulate material(s) is preferablyabout 5 to about 50% by weight, preferably about 10 to about 35% byweight.

In the context of the present invention, the organic particulatematerial may be a latex material, organic crystals or a solidplasticizer as described below.

In one embodiment of this aspect of the invention, the adhesive layermay comprise an adhesive binder, a polymeric particulate material, afirst inorganic particulate material having an average particle size oflarger than about 0.5 to about 6 um, preferably larger than about 1 toabout 3 um, and a second inorganic particulate material having anaverage particle size smaller than about 0.2 um, preferably smaller thanabout 0.1 um and more preferably smaller than about 0.05 um. The totalconcentration of the inorganic particulate materials is preferably about5 to about 50% by weight, preferably about 10 to about 35% by weight.The concentration of the polymeric particulate material is preferably inthe range of about 5 to about 50% by weight, more preferably in therange of about 10 to about 40% by weight. The polymeric particulatematerial is preferably small particles having an average size of < about1 um, preferably < about 0.2 um and more preferably < about 0.15 um.

In another aspect of the present invention, the adhesive layer maycomprise a solid plasticizer having a melting temperature between about65° C. to about 130° C., preferably between about 80° C. to about 115°C. Examples of such solid plasticizers may include, but are not limitedto, BHT (2,6-di-t-butyl-4-methylphenol), thiodiethylene hydrocinnamate(IRGANOX™ 1035 from Ciba-Geigy Corp.), tetrakis hindered phenol such asIRGANOX™ 1010 from Ciba Geigy Corp., dicyclohexyl phthalate, diphenylphthalate, ethylene glycol dibenzoate,2,2′-dihydroxy-4-methoxybenzophenone,2,2′-dihydroxy-4-methoxybenzophenone, diphenyl oxalate, benzyloxynaphthalene, 1-hydroxy-2-naphthoate, rosin and m-terphenylderivatives, as well as many of the heat meltable crystalline compoundsdisclosed in U.S. Pat. No. 4,885,271, the content of which isincorporated herein by reference in its entirety.

The solid plasticizer may have an average particle size between about0.05 microns to about 5 microns, preferably between 0.1 microns to about3 microns. The solid plasticizer may take up between about 1% to about10%, preferably about 2% to about 8% by weight, of the adhesive layercomposition.

The components of the adhesive layer may be dispersed in a suitablecarrier solvent or solvent mixture that does not attack the underlyinglayers during coating and drying. Water and hydrocarbon solvents (suchas naphtha and toluene, etc.) are the preferred carriers for theadhesive composition, with water as the most preferred.

In the formation of the in-mold decorative tape or strip (10), therelease layer (11), the durable layer (12), the decorative design layer(13) and the adhesive layer (14) of the present invention aresequentially coated or laminated onto the carrier layer (15). Thelamination or coating may be accomplished by a coating method such asslot coating, doctor blade coating, gravure coating, roll coating, commacoating, lip coating, vacuum deposition, sputtering or the like or aprinting method such as gravure printing, screen printing, flexoprinting, lithographic printing, driographic printing or the like.

The durable layer and release layer may be thermal cured during thedrying of the durable layer coating step, optionally with a post curestep after the coating. The thermal cure can be carried out at about 50°C. to about 120° C. for various lengths of time, for example, tenths ofminute to hours, depending on the curing conditions and the composition.

To further improve the physicomechanical properties, the decoration orfunctional film may be further UV cured after the injection moldingprocess when it has been transferred to the surface of the moldedobject. The molded object is placed on a UV conveyor that is running at,for example, 0.6 ft/min to 10 ft/min. The UV curing energy needed isusually in the range of from about 0.1 to about 5 J/cm², preferablyabout 0.3 to about 1.2 J/cm².

The adhesive layer of the present invention provides desirable fractureproperties and as a result, cracking at the edges of the object duringthe transfer process, such as injection molding, may be initiated andpropagated efficiently during the injection molding process and thesubsequent mold-part separation process. This feature enables a cleanseparation of the decoration or functional layer from the carriersubstrate at the edges of the object, particularly at the edges of ahollow structure.

In addition, the adhesive layer of the present invention also provideshigh degree of transmission, high blocking resistance, high hardness andsufficient adhesion, even for complicated three-dimensional objects.

The adhesive layer of the present invention is suitable for all in-molddecoration processes for the manufacture of a plastic object. Examplesof the material suitable for the object may include, but are not limitedto, thermoplastic materials such as polystyrene, polyvinyl chloride,acrylics, polysulfone, polyarylester, polypropylene oxide, polyolefins,acrylonitrile-butadiene-styrene copolymers (ABS),methacrylate-acrylonitrile-butadiene-styrene copolymers (MABS),polycarbonate, polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polyurethanes and other thermoplastic elastomers orblends thereof, and thermoset materials such as reaction injectionmolding grade polyurethanes, epoxy resin, unsaturated polyesters,vinylesters or composites, prepregs and blends thereof.

The object may be a plastic cover of a cell phone or pager. In fact, theadhesive layer is useful for any plastic objects manufactured from anin-mold decoration process, such as personal accessories, toys oreducational devices, plastic cover of a personal digital assistant ore-book, credit or smart cards, identification or business cards, face ofan album, watch, clock, radio or camera, dashboard in an automobile,household items, laptop computer housings and carrying cases or frontcontrol panels of any consumer electronic equipments. This is clearlynot exhaustive. Other suitable plastic objects would be clear to aperson skilled in the art and therefore they are all encompassed withinthe scope of the present invention. The adhesive layer of the presentinvention is also useful in applications such as the thermal transferprotective coating for thermal printing, inkjet printing and passportand other identification applications.

EXAMPLES Example 1

A release fluid was prepared first by mixing 2.10 gm of MF370(methylated melamine resin, Cytec Industries) with 1.41 gm of ethyleneglycol dimethyl ether (Aldrich) and 0.63 gm of DI water using a magneticstirrer, after which 0.6 gm of 2,2′-dihydroxy-4-methoxybenzophenone(Aldrich), 0.06 gm of Silwet L7230/SL7607 (3/1 weight ratio, from OsiSpecialties, Inc.) and 0.2 gm of Cycat 4040 (p-toluene sulfonic acid,from Cytec Industry) were added with agitation to ensure a homogeneoussolution. This release fluid was then coated on a 1.5 mil PET film (PT1from Mitsubishi Interfilm Holding, Inc., Easley, S.C.) with a #6.5 rodand a target dry coating thickness of 1.5 um. The coating was thenplaced in a 120° C. oven for 5 minutes to form a release coating.

A durable layer composition consisting of 7.67 gm (15% in MEK) ofCAB-553-0.4 (cellulose acetate butyrate, from Eastman Chemical Co.),2.94 gm (50% in MEK) of Ebecryl 1290 (aliphatic polyurethane acrylate,UCB Chemicals), 1.2 gm (30% in MEK) of MEK-ST (a silica dispersion fromNissan Chemicals), 0.40 gm of (25% in MEK) 1:1 w % ratio oftriethanolamine and poly-Q (aminated tetrol from Arch Chemicals,Norwalk, Conn.), 0.43 gm of a photoinitiator (PI) solution containing1.5% of BMS (4-(p-tolylthio)benzophenone, Aldrich, Milwaukee, Wis.),0.8% of Irgacure 651 (2,2-dimethoxy-1,2-diphenylethane, Ciba SpecialityChemicals, Tarrytown, N.Y.), 0.15% of ITX (isopropyl thioxanthone,Aldrich, Milwaukee, Wis.), 0.2% of DBTDL (dibutyltin dilaurate, Aldrich,Milwaukee, Wis.), 0.1% of Irganox 1035 (thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], Ciba SpecialityChemicals, Tarrytown, N.Y.) and 0.2% of Tinuvin 123 [decanedioic acid,bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, reactionproducts with 1,1-dimethylethylhydroperoxide and octane from CibaSpeciality Chemicals, Tarrytown, N.Y.] in MEK, was prepared. Thecomposition was overcoated onto the release layer prepared above using a#28 Meyer bar with a target thickness of about 7 um and dried at 70° C.for 20 minutes. The dried durable coating was then exposed to 0.4 J/cm2UV irradiation.

Before preparing an adhesive composition of the present invention, thepH of each of the materials used was adjusted to 7.5 with either adiluted ammonia solution or a diluted sulfuric acid solution. Theadhesive composition was then prepared by mixing 6.947 gm of S-2725(water borne polyurethane) of a 40% solid content (from Neveon), 8.154gm of AquaPress ME of a 39% solid content (from Proell Inc) and.9.611 gmof DI water together.

To the mixture, 2.897 gm of S-50 (silica nanoparticles) of a solidcontent of 29% (Nissan Chemical Houston Corporation) and 2.391 gm ofNeoCryl A-550 (water borne acrylic resin) of a solid content of 27.6%(Tg=100° C., from NeoResins) were added in sequence with agitation.

The adhesive composition was then coated onto the durable layer preparedabove with a #11 wired rod and dried in an 80° C. oven for 10 minutes.The adhesive coating thickness was targeted at ˜3 um.

The film sample was then tested using a direct injection molding methodwith PMMA resin ZKM (from CYRO Industries) at 480° F.

Example 2 Comparative Example

8.154 Grams of AquaPress ME and 7.74 gm of DI water were mixed together.The resulting mixture was coated onto the durable layer prepared inExample 1 and dried in an 80° C. oven for 10 minutes. The film samplewas then tested using a direct injection molding method with PMMA resinZKM (from CYRO Industries) at 480° F. TABLE 1 Trans- Film Blocking atAd- Lens Edge parency of 40° C./90% hesion Cleanness the Lens RH & 60Hours Example 1 good excellent excellent pass Example 2 good 90% filmexcellent fail (Comparative remaining with Example) the lens

Examples 3-5 The Use of Organic Particles with Different Tgs

In these examples, the pH values of all the materials used werepre-adjusted to 8.5 prior to mixing.

1.303 Grams of S-2725 (water borne polyurethane) of a 19% solid content(from Neveon), 4.523 gm of AquaPress ME of a 39% solid content (fromProell Inc) and 7.0 gm of DI water were mixed together. To this mixture,0.84 gm of S-50 (silica nanoparticles) of a solid content of 29% (fromNissan Chemical Houston Corporation) was added, followed by adding 1.15gm of B-85 (non-crosslinking acrylic emulsion) of a 31.3% solid content(Tg=73° C., Rohm & Haas) with agitation (in Example 3). In Example 4,1.125 gm of NeoCryl A-6015 (acrylic emulsion) of a 32% solid content(Tg=63° C., NeoResins) was added. In Example 5, 0.818 gm of CL-106(acrylic resin) of a 44% solid content (Tg=46° C., Rohm & Haas) wasadded. An additional 0.184 gm, 0.209 gm and 0.516 gm of water were addedinto Formulations of Example 3, Example 4 and Example 5, respectively,to make up a total solid content of 20%. The adhesive solution was thencoated on the durable layer prepared in Example 1 with a #11 wired rodand dried in an 80° C. oven for 10 minutes. The adhesive coatingthickness was targeted at ˜3 um.

The film samples were then tested using a direct injection moldingmethod with PMMA resin ZKM (from CYRO Industries) at 480° F. Theresultant lens showed clean edges.

Example 6 The Use of Organic Particles with Two Different InorganicParticles (CaCO₃ and Silica) and a Solid Plasticizer

Socal S31 (CaCO₃) was ground to an average particle size of 0.3 um usingZrconium beads, Triton X-100 (Aldrich) and Tamol 731A (from Rohm Haas)at 12° C.

A solid plasticizer, 1,2-diphenoxyethane (melting temperature of 95°C.), was ground in the presence of a wetting agent, Triton X100, and adispersing agent, Tamol 731A. The grinding temperature was 4° C. andgrinding time was 14 hours. The particle size under microscope was about1 to 2 um and the solution pH was 8.4.

0.928 Grams of S-2725 (water borne polyurethane) of a 40% solid content(from Neveon) was mixed with 2.22 gm of AquaPress ME of a 39% solidcontent (from Proell Inc) and 2.831 gm of DI water. To this mixture, 0.5gm of S-50 (silica nanoparticles) of a 40% solid content (NissanChemical Houston Corporation), 1.206 gm of a CaCO₃ dispersion of a 31.1%solid content prepared above and 0.791 grams of the solid plasticizerdispersion of a 15.8% solid content prepared above, were added. Themixture was vortexed for 2 minutes. To this mixture, 5.876 gm of NeoCrylA-550 (water borne acrylic resin) of a 9.57% solid content (NeoResins)was added and the fluid was vortexed for 2 additional minutes. Theadhesive solution was then coated on the durable layer preparedaccording to Example 1 with a #11 wired rod and dried in an 80° C. ovenfor 10 minutes. The adhesive coating thickness was targeted at ˜3 um.

The film sample was then tested using a direct injection molding methodwith PMMA resin ZKM (from CYRO Industries) at 480° F. The resulted lenshad clean edges.

Example 7 Comparative Example

The use of organic particles and a solid plasticizer without inorganicparticles was tested.

1.312 Grams of S-2725 (water borne polyurethane) of a 40% solid content(from Neveon) was mixed with 3.14 gm of AquaPress ME of a 39% solidcontent (from Proell Inc) and 1.38 gm of DI water. To this mixture,0.791 gm of the solid plasticizer dispersion of a 15.8% solid contentprepared in Example 6 was added. The mixture was vortexed for 2minitues. 5.876 Grams of NeoCryl A-550 (water borne acrylic resin) of a10.64% solid content (NeoResins) was added and the fluid was vortexedfor 2 additioal minutes. The adhesive solution was coated on the durablelayer prepared according to Example 1 with a #11 wired rod and dried inan 80° C. oven for 10 minutes. The adhesive coating thickness wastargeted at ˜3 um.

The film sample was then tested using a direct injection molding methodwith PMMA resin ZKM (from CYRO Industries) at 480° F. The lens formedhad only 20% edge film removed.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, materials, compositions, processes, process stepor steps, to the objective and scope of the present invention. All suchmodifications are intended to be within the scope of the claims appendedhereto.

1. An adhesive layer for in-mold decoration which comprises an adhesivebinder and a polymeric particulate material.
 2. The adhesive layer ofclaim 1 wherein said adhesive binder is selected from the groupconsisting of polyurethane, acrylics, SBR (styrene-butadiene rubber),polybutadiene, polyamides, pyrrolidone copolymers, oxazolidonecopolymers, vinylidene chloride copolymers, vinylacetate copolymers,polyesters and derivatives or blends thereof.
 3. The adhesive layer ofclaim 1 wherein said adhesive binder is a polyurethane, acrylic or ahybrid thereof.
 4. The adhesive layer of claim 1 wherein said adhesivebinder is a latex adhesive binder or a hydrocarbon dispersion adhesive.5. The adhesive layer of claim 1 wherein said adhesive binder takes upabout 40% to about 90% by weight of the adhesive layer.
 6. The adhesivelayer of claim 1 wherein said polymeric particulate material has a glasstransition temperature higher than about 45° C.
 7. The adhesive layer ofclaim 1 wherein said polymeric particulate material has an averageparticle size of less than about 1 um.
 8. The adhesive layer of claim 1wherein said polymeric particulate material takes up about 5 to about50% by weight of the adhesive layer.
 9. The adhesive layer of claim 1wherein said polymeric particulate material is refractive index matchedto said adhesive binder.
 10. The adhesive layer of claim 1 wherein thedifference between refractive indexes of said polymeric particulatematerial and said adhesive binder is less than about 0.1.
 11. Theadhesive layer of claim 1 wherein said polymeric particulate material iscore-shell particles.
 12. The adhesive layer of claim 11 wherein saidshell has a glass transition temperature of higher than about 45° C. 13.The adhesive layer of claim 11 wherein said core is refractive indexmatched to the shell or a blend of the shell and the adhesive binder.14. The adhesive layer of claim 1 further comprising an inorganicparticulate material.
 15. The adhesive layer of claim 14 wherein saidinorganic particulate material is CaCO₃, BaSO₄, silica, glass beads,bentonite or clay.
 16. The adhesive layer of claim 14 wherein saidinorganic particulate material takes up about 1 to about 20% by weightof the adhesive layer.
 17. The adhesive layer of claim 14 wherein saidinorganic particulate material has an average particle size of less thanabout 0.2 um.
 18. The adhesive layer of claim 1 further comprising anorganic or inorganic particulate material.
 19. The adhesive layer ofclaim 18 wherein said organic particulate material is a latex material,organic crystals or a solid plasticizer.
 20. The adhesive layer of claim18 wherein said inorganic particulate material is CaCO₃, BaSO₄, silica,glass beads, bentonite or clay.
 21. The adhesive layer of claim 18wherein said organic or inorganic particulate material takes up about0.2 to about 5% by weight of the adhesive layer.
 22. The adhesive layerof claim 18 wherein said organic or inorganic particulate material hasan average particle size in the range of about 0.5 to about 6 um.
 23. Anadhesive layer for in-mold decoration which comprises an adhesivebinder, a polymeric particulate material, an organic or a firstinorganic particulate material and a second inorganic particulatematerial.
 24. The adhesive layer of claim 23 wherein said first andsecond inorganic particulate materials are independently CaCO₃, BaSO₄,silica, glass beads, bentonite or clay.
 25. The adhesive layer of claim23 wherein said organic or first inorganic particulate material has anaverage particle size in the range of about 0.5 to about 6 um.
 26. Theadhesive layer of claim 23 wherein said second inorganic particulatematerial has an average particle size smaller than about 0.2 um.
 27. Theadhesive layer of claim 23 wherein the total concentration of saidinorganic particulate material(s) is about 5 to about 50% by weight. 28.The adhesive layer of claim 1 which is dispersed in a carrier.
 29. Theadhesive layer of claim 28 wherein said carrier is water or ahydrocarbon solvent.
 30. The adhesive layer of claim 1 furthercomprising a solid plasticizer.